Kirchhoff's voltage law applied to the circuit loop

Steps:

• Identify the total battery voltage as the sum of all potential differences around the loop.
• Add the given voltages: 2V + 3V + 5V + 1.2V + 2.4V = 13.6V, so battery is 18V.
• The potential difference across R is battery voltage minus sum of others: 18V - 13.6V = 4.4V.
• Verify no current branches affect the loop sum.

Why A is correct:

• Kirchhoff's voltage law states the algebraic sum of voltages in a closed loop is zero, directly yielding 4.4V for R.

Why the others are wrong:

• B: Ignores full loop sum, underestimating by partial voltages.
• C: Assumes equal division, violating actual network configuration.
• D: Overadds voltages, confusing series with parallel paths.

Final answer: A